There is also a rock sample known composition for the APXS instrument to work on. This is a type of instrument that helps determine what something is made of.

There are five sealed organic check materials for the rover to drill into, collect, and analyze with its chemistry instruments. These are made up of a known material that scientists are sure will not be found in nature. If organics are found, these can be tested to see if the instruments give the right results with a known material and are not just some containment.